Auto merge of #117415 - matthiaskrgr:rollup-jr2p1t2, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #116862 (Detect when trait is implemented for type and suggest importing it)
 - #117389 (Some diagnostics improvements of `gen` blocks)
 - #117396 (Don't treat closures/coroutine types as part of the public API)
 - #117398 (Correctly handle nested or-patterns in exhaustiveness)
 - #117403 (Poison check_well_formed if method receivers are invalid to prevent typeck from running on it)
 - #117411 (Improve some diagnostics around `?Trait` bounds)
 - #117414 (Don't normalize to an un-revealed opaque when we hit the recursion limit)

r? `@ghost`
`@rustbot` modify labels: rollup

compiler/rustc_hir_analysis/src/astconv/bounds.rs

@@ -8,6 +8,7 @@ use rustc_middle::ty::{self as ty, Ty, TypeVisitableExt};
 use rustc_span::symbol::Ident;
 use rustc_span::{ErrorGuaranteed, Span};
 use rustc_trait_selection::traits;
+use smallvec::SmallVec;
 
 use crate::astconv::{
     AstConv, ConvertedBinding, ConvertedBindingKind, OnlySelfBounds, PredicateFilter,
@@ -28,15 +29,11 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
         let tcx = self.tcx();
 
         // Try to find an unbound in bounds.
-        let mut unbound = None;
+        let mut unbounds: SmallVec<[_; 1]> = SmallVec::new();
         let mut search_bounds = |ast_bounds: &'tcx [hir::GenericBound<'tcx>]| {
             for ab in ast_bounds {
                 if let hir::GenericBound::Trait(ptr, hir::TraitBoundModifier::Maybe) = ab {
-                    if unbound.is_none() {
+                    unbounds.push(ptr)
-                        unbound = Some(&ptr.trait_ref);
-                    } else {
-                        tcx.sess.emit_err(errors::MultipleRelaxedDefaultBounds { span });
-                    }
                 }
             }
         };
@@ -51,33 +48,41 @@ impl<'tcx> dyn AstConv<'tcx> + '_ {
             }
         }
 
-        let sized_def_id = tcx.lang_items().sized_trait();
+        if unbounds.len() > 1 {
-        match (&sized_def_id, unbound) {
+            tcx.sess.emit_err(errors::MultipleRelaxedDefaultBounds {
-            (Some(sized_def_id), Some(tpb))
+                spans: unbounds.iter().map(|ptr| ptr.span).collect(),
-                if tpb.path.res == Res::Def(DefKind::Trait, *sized_def_id) =>
+            });
-            {
-                // There was in fact a `?Sized` bound, return without doing anything
-                return;
-            }
-            (_, Some(_)) => {
-                // There was a `?Trait` bound, but it was not `?Sized`; warn.
-                tcx.sess.span_warn(
-                    span,
-                    "default bound relaxed for a type parameter, but \
-                        this does nothing because the given bound is not \
-                        a default; only `?Sized` is supported",
-                );
-                // Otherwise, add implicitly sized if `Sized` is available.
-            }
-            _ => {
-                // There was no `?Sized` bound; add implicitly sized if `Sized` is available.
-            }
         }
+
+        let sized_def_id = tcx.lang_items().sized_trait();
+
+        let mut seen_sized_unbound = false;
+        for unbound in unbounds {
+            if let Some(sized_def_id) = sized_def_id {
+                if unbound.trait_ref.path.res == Res::Def(DefKind::Trait, sized_def_id) {
+                    seen_sized_unbound = true;
+                    continue;
+                }
+            }
+            // There was a `?Trait` bound, but it was not `?Sized`; warn.
+            tcx.sess.span_warn(
+                unbound.span,
+                "relaxing a default bound only does something for `?Sized`; \
+                all other traits are not bound by default",
+            );
+        }
+
+        // If the above loop finished there was no `?Sized` bound; add implicitly sized if `Sized` is available.
         if sized_def_id.is_none() {
             // No lang item for `Sized`, so we can't add it as a bound.
             return;
         }
-        bounds.push_sized(tcx, self_ty, span);
+        if seen_sized_unbound {
+            // There was in fact a `?Sized` bound, return without doing anything
+        } else {
+            // There was no `?Sized` bound; add implicitly sized if `Sized` is available.
+            bounds.push_sized(tcx, self_ty, span);
+        }
     }
 
     /// This helper takes a *converted* parameter type (`param_ty`)

compiler/rustc_hir_analysis/src/check/wfcheck.rs

@@ -94,7 +94,7 @@ pub(super) fn enter_wf_checking_ctxt<'tcx, F>(
     f: F,
 ) -> Result<(), ErrorGuaranteed>
 where
-    F: for<'a> FnOnce(&WfCheckingCtxt<'a, 'tcx>),
+    F: for<'a> FnOnce(&WfCheckingCtxt<'a, 'tcx>) -> Result<(), ErrorGuaranteed>,
 {
     let param_env = tcx.param_env(body_def_id);
     let infcx = &tcx.infer_ctxt().build();
@@ -105,7 +105,7 @@ where
     if !tcx.features().trivial_bounds {
         wfcx.check_false_global_bounds()
     }
-    f(&mut wfcx);
+    f(&mut wfcx)?;
 
     let assumed_wf_types = wfcx.ocx.assumed_wf_types_and_report_errors(param_env, body_def_id)?;
 
@@ -875,6 +875,7 @@ fn check_param_wf(tcx: TyCtxt<'_>, param: &hir::GenericParam<'_>) -> Result<(),
                         ty,
                         trait_def_id,
                     );
+                    Ok(())
                 })
             } else {
                 let mut diag = match ty.kind() {
@@ -961,6 +962,7 @@ fn check_associated_item(
                 let ty = tcx.type_of(item.def_id).instantiate_identity();
                 let ty = wfcx.normalize(span, Some(WellFormedLoc::Ty(item_id)), ty);
                 wfcx.register_wf_obligation(span, loc, ty.into());
+                Ok(())
             }
             ty::AssocKind::Fn => {
                 let sig = tcx.fn_sig(item.def_id).instantiate_identity();
@@ -972,7 +974,7 @@ fn check_associated_item(
                     hir_sig.decl,
                     item.def_id.expect_local(),
                 );
-                check_method_receiver(wfcx, hir_sig, item, self_ty);
+                check_method_receiver(wfcx, hir_sig, item, self_ty)
             }
             ty::AssocKind::Type => {
                 if let ty::AssocItemContainer::TraitContainer = item.container {
@@ -983,6 +985,7 @@ fn check_associated_item(
                     let ty = wfcx.normalize(span, Some(WellFormedLoc::Ty(item_id)), ty);
                     wfcx.register_wf_obligation(span, loc, ty.into());
                 }
+                Ok(())
             }
         }
     })
@@ -1097,6 +1100,7 @@ fn check_type_defn<'tcx>(
         }
 
         check_where_clauses(wfcx, item.span, item.owner_id.def_id);
+        Ok(())
     })
 }
 
@@ -1121,7 +1125,8 @@ fn check_trait(tcx: TyCtxt<'_>, item: &hir::Item<'_>) -> Result<(), ErrorGuarant
     }
 
     let res = enter_wf_checking_ctxt(tcx, item.span, def_id, |wfcx| {
-        check_where_clauses(wfcx, item.span, def_id)
+        check_where_clauses(wfcx, item.span, def_id);
+        Ok(())
     });
 
     // Only check traits, don't check trait aliases
@@ -1164,6 +1169,7 @@ fn check_item_fn(
     enter_wf_checking_ctxt(tcx, span, def_id, |wfcx| {
         let sig = tcx.fn_sig(def_id).instantiate_identity();
         check_fn_or_method(wfcx, ident.span, sig, decl, def_id);
+        Ok(())
     })
 }
 
@@ -1218,6 +1224,7 @@ fn check_item_type(
                 tcx.require_lang_item(LangItem::Sync, Some(ty_span)),
             );
         }
+        Ok(())
     })
 }
 
@@ -1276,6 +1283,7 @@ fn check_impl<'tcx>(
         }
 
         check_where_clauses(wfcx, item.span, item.owner_id.def_id);
+        Ok(())
     })
 }
 
@@ -1548,11 +1556,11 @@ fn check_method_receiver<'tcx>(
     fn_sig: &hir::FnSig<'_>,
     method: ty::AssocItem,
     self_ty: Ty<'tcx>,
-) {
+) -> Result<(), ErrorGuaranteed> {
     let tcx = wfcx.tcx();
 
     if !method.fn_has_self_parameter {
-        return;
+        return Ok(());
     }
 
     let span = fn_sig.decl.inputs[0].span;
@@ -1571,11 +1579,11 @@ fn check_method_receiver<'tcx>(
     if tcx.features().arbitrary_self_types {
         if !receiver_is_valid(wfcx, span, receiver_ty, self_ty, true) {
             // Report error; `arbitrary_self_types` was enabled.
-            e0307(tcx, span, receiver_ty);
+            return Err(e0307(tcx, span, receiver_ty));
         }
     } else {
         if !receiver_is_valid(wfcx, span, receiver_ty, self_ty, false) {
-            if receiver_is_valid(wfcx, span, receiver_ty, self_ty, true) {
+            return Err(if receiver_is_valid(wfcx, span, receiver_ty, self_ty, true) {
                 // Report error; would have worked with `arbitrary_self_types`.
                 feature_err(
                     &tcx.sess.parse_sess,
@@ -1587,16 +1595,17 @@ fn check_method_receiver<'tcx>(
                     ),
                 )
                 .help(HELP_FOR_SELF_TYPE)
-                .emit();
+                .emit()
             } else {
                 // Report error; would not have worked with `arbitrary_self_types`.
-                e0307(tcx, span, receiver_ty);
+                e0307(tcx, span, receiver_ty)
-            }
+            });
         }
     }
+    Ok(())
 }
 
-fn e0307(tcx: TyCtxt<'_>, span: Span, receiver_ty: Ty<'_>) {
+fn e0307(tcx: TyCtxt<'_>, span: Span, receiver_ty: Ty<'_>) -> ErrorGuaranteed {
     struct_span_err!(
         tcx.sess.diagnostic(),
         span,
@@ -1605,7 +1614,7 @@ fn e0307(tcx: TyCtxt<'_>, span: Span, receiver_ty: Ty<'_>) {
     )
     .note("type of `self` must be `Self` or a type that dereferences to it")
     .help(HELP_FOR_SELF_TYPE)
-    .emit();
+    .emit()
 }
 
 /// Returns whether `receiver_ty` would be considered a valid receiver type for `self_ty`. If

compiler/rustc_hir_analysis/src/errors.rs

@@ -96,7 +96,7 @@ pub struct CopyImplOnTypeWithDtor {
 #[diag(hir_analysis_multiple_relaxed_default_bounds, code = "E0203")]
 pub struct MultipleRelaxedDefaultBounds {
     #[primary_span]
-    pub span: Span,
+    pub spans: Vec<Span>,
 }
 
 #[derive(Diagnostic)]

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -35,6 +35,7 @@ use rustc_span::def_id::DefIdSet;
 use rustc_span::symbol::{kw, sym, Ident};
 use rustc_span::Symbol;
 use rustc_span::{edit_distance, source_map, ExpnKind, FileName, MacroKind, Span};
+use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::error_reporting::on_unimplemented::OnUnimplementedNote;
 use rustc_trait_selection::traits::error_reporting::on_unimplemented::TypeErrCtxtExt as _;
 use rustc_trait_selection::traits::query::evaluate_obligation::InferCtxtExt as _;
@@ -192,7 +193,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                     .span_if_local(def_id)
                     .unwrap_or_else(|| self.tcx.def_span(def_id));
                 err.span_label(sp, format!("private {kind} defined here"));
-                self.suggest_valid_traits(&mut err, out_of_scope_traits);
+                self.suggest_valid_traits(&mut err, out_of_scope_traits, true);
                 err.emit();
             }
 
@@ -2464,6 +2465,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         &self,
         err: &mut Diagnostic,
         valid_out_of_scope_traits: Vec<DefId>,
+        explain: bool,
     ) -> bool {
         if !valid_out_of_scope_traits.is_empty() {
             let mut candidates = valid_out_of_scope_traits;
@@ -2476,7 +2478,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 .find(|did| self.tcx.is_diagnostic_item(sym::TryInto, **did))
                 .copied();
 
-            err.help("items from traits can only be used if the trait is in scope");
+            if explain {
+                err.help("items from traits can only be used if the trait is in scope");
+            }
             let msg = format!(
                 "the following {traits_are} implemented but not in scope; \
                  perhaps add a `use` for {one_of_them}:",
@@ -2693,7 +2697,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 }
             }
         }
-        if self.suggest_valid_traits(err, valid_out_of_scope_traits) {
+        if self.suggest_valid_traits(err, valid_out_of_scope_traits, true) {
             return;
         }
 
@@ -2970,22 +2974,39 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 (candidates, Vec::new())
             };
 
+            let impls_trait = |def_id: DefId| {
+                let args = ty::GenericArgs::for_item(self.tcx, def_id, |param, _| {
+                    if param.index == 0 {
+                        rcvr_ty.into()
+                    } else {
+                        self.infcx.var_for_def(span, param)
+                    }
+                });
+                self.infcx
+                    .type_implements_trait(def_id, args, self.param_env)
+                    .must_apply_modulo_regions()
+                    && param_type.is_none()
+            };
             match &potential_candidates[..] {
                 [] => {}
                 [trait_info] if trait_info.def_id.is_local() => {
-                    err.subdiagnostic(CandidateTraitNote {
+                    if impls_trait(trait_info.def_id) {
-                        span: self.tcx.def_span(trait_info.def_id),
+                        self.suggest_valid_traits(err, vec![trait_info.def_id], false);
-                        trait_name: self.tcx.def_path_str(trait_info.def_id),
+                    } else {
-                        item_name,
+                        err.subdiagnostic(CandidateTraitNote {
-                        action_or_ty: if trait_missing_method {
+                            span: self.tcx.def_span(trait_info.def_id),
-                            "NONE".to_string()
+                            trait_name: self.tcx.def_path_str(trait_info.def_id),
-                        } else {
+                            item_name,
-                            param_type.map_or_else(
+                            action_or_ty: if trait_missing_method {
-                                || "implement".to_string(), // FIXME: it might only need to be imported into scope, not implemented.
+                                "NONE".to_string()
-                                ToString::to_string,
+                            } else {
-                            )
+                                param_type.map_or_else(
-                        },
+                                    || "implement".to_string(), // FIXME: it might only need to be imported into scope, not implemented.
-                    });
+                                    ToString::to_string,
+                                )
+                            },
+                        });
+                    }
                 }
                 trait_infos => {
                     let mut msg = message(param_type.map_or_else(
@@ -2993,6 +3014,9 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         |param| format!("restrict type parameter `{param}` with"),
                     ));
                     for (i, trait_info) in trait_infos.iter().enumerate() {
+                        if impls_trait(trait_info.def_id) {
+                            self.suggest_valid_traits(err, vec![trait_info.def_id], false);
+                        }
                         msg.push_str(&format!(
                             "\ncandidate #{}: `{}`",
                             i + 1,

compiler/rustc_middle/messages.ftl

@@ -12,6 +12,8 @@ middle_assert_coroutine_resume_after_return = coroutine resumed after completion
 middle_assert_divide_by_zero =
     attempt to divide `{$val}` by zero
 
+middle_assert_gen_resume_after_panic = `gen` fn or block cannot be further iterated on after it panicked
+
 middle_assert_misaligned_ptr_deref =
     misaligned pointer dereference: address must be a multiple of {$required} but is {$found}
 

compiler/rustc_middle/src/mir/terminator.rs

@@ -250,8 +250,7 @@ impl<O> AssertKind<O> {
                 middle_assert_coroutine_resume_after_return
             }
             ResumedAfterPanic(CoroutineKind::Async(_)) => middle_assert_async_resume_after_panic,
-            // FIXME(gen_blocks): custom error message for `gen` blocks
+            ResumedAfterPanic(CoroutineKind::Gen(_)) => middle_assert_gen_resume_after_panic,
-            ResumedAfterPanic(CoroutineKind::Gen(_)) => middle_assert_async_resume_after_panic,
             ResumedAfterPanic(CoroutineKind::Coroutine) => {
                 middle_assert_coroutine_resume_after_panic
             }

compiler/rustc_mir_build/src/thir/pattern/usefulness.rs

@@ -931,7 +931,7 @@ impl<'p, 'tcx> PatternColumn<'p, 'tcx> {
             let specialized = pat.specialize(pcx, &ctor);
             for (subpat, column) in specialized.iter().zip(&mut specialized_columns) {
                 if subpat.is_or_pat() {
-                    column.patterns.extend(subpat.iter_fields())
+                    column.patterns.extend(subpat.flatten_or_pat())
                 } else {
                     column.patterns.push(subpat)
                 }

compiler/rustc_parse/messages.ftl

@@ -278,8 +278,8 @@ parse_found_expr_would_be_stmt = expected expression, found `{$token}`
 parse_function_body_equals_expr = function body cannot be `= expression;`
     .suggestion = surround the expression with `{"{"}` and `{"}"}` instead of `=` and `;`
 
-parse_gen_block = `gen` blocks are not yet implemented
+parse_gen_fn = `gen` functions are not yet implemented
-    .help = only the keyword is reserved for now
+    .help = for now you can use `gen {"{}"}` blocks and return `impl Iterator` instead
 
 parse_generic_args_in_pat_require_turbofish_syntax = generic args in patterns require the turbofish syntax
 

compiler/rustc_parse/src/errors.rs

@@ -521,9 +521,9 @@ pub(crate) struct CatchAfterTry {
 }
 
 #[derive(Diagnostic)]
-#[diag(parse_gen_block)]
+#[diag(parse_gen_fn)]
 #[help]
-pub(crate) struct GenBlock {
+pub(crate) struct GenFn {
     #[primary_span]
     pub span: Span,
 }

compiler/rustc_parse/src/parser/item.rs

@@ -2372,7 +2372,7 @@ impl<'a> Parser<'a> {
         }
 
         if let Gen::Yes { span, .. } = genness {
-            self.sess.emit_err(errors::GenBlock { span });
+            self.sess.emit_err(errors::GenFn { span });
         }
 
         if !self.eat_keyword_case(kw::Fn, case) {

compiler/rustc_trait_selection/src/traits/query/normalize.rs

@@ -230,17 +230,14 @@ impl<'cx, 'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for QueryNormalizer<'cx, 'tcx>
                     Reveal::All => {
                         let args = data.args.try_fold_with(self)?;
                         let recursion_limit = self.interner().recursion_limit();
+
                         if !recursion_limit.value_within_limit(self.anon_depth) {
-                            // A closure or coroutine may have itself as in its upvars.
+                            let guar = self
-                            // This should be checked handled by the recursion check for opaque
+                                .infcx
-                            // types, but we may end up here before that check can happen.
-                            // In that case, we delay a bug to mark the trip, and continue without
-                            // revealing the opaque.
-                            self.infcx
                                 .err_ctxt()
                                 .build_overflow_error(&ty, self.cause.span, true)
                                 .delay_as_bug();
-                            return ty.try_super_fold_with(self);
+                            return Ok(Ty::new_error(self.interner(), guar));
                         }
 
                         let generic_ty = self.interner().type_of(data.def_id);

compiler/rustc_ty_utils/src/opaque_types.rs

@@ -121,6 +121,7 @@ impl<'tcx> OpaqueTypeCollector<'tcx> {
 }
 
 impl<'tcx> super::sig_types::SpannedTypeVisitor<'tcx> for OpaqueTypeCollector<'tcx> {
+    #[instrument(skip(self), ret, level = "trace")]
     fn visit(&mut self, span: Span, value: impl TypeVisitable<TyCtxt<'tcx>>) -> ControlFlow<!> {
         self.visit_spanned(span, value);
         ControlFlow::Continue(())

compiler/rustc_ty_utils/src/sig_types.rs

@@ -4,7 +4,7 @@
 use std::ops::ControlFlow;
 
 use rustc_hir::{def::DefKind, def_id::LocalDefId};
-use rustc_middle::ty::{self, TyCtxt};
+use rustc_middle::ty::TyCtxt;
 use rustc_span::Span;
 use rustc_type_ir::visit::TypeVisitable;
 
@@ -25,24 +25,9 @@ pub fn walk_types<'tcx, V: SpannedTypeVisitor<'tcx>>(
     let kind = tcx.def_kind(item);
     trace!(?kind);
     match kind {
-        DefKind::Coroutine => {
+        // Walk over the signature of the function
-            match tcx.type_of(item).instantiate_identity().kind() {
+        DefKind::AssocFn | DefKind::Fn => {
-                ty::Coroutine(_, args, _) => visitor.visit(tcx.def_span(item), args.as_coroutine().sig())?,
+            let ty_sig = tcx.fn_sig(item).instantiate_identity();
-                _ => bug!(),
-            }
-            for (pred, span) in tcx.predicates_of(item).instantiate_identity(tcx) {
-                visitor.visit(span, pred)?;
-            }
-        }
-        // Walk over the signature of the function-like
-        DefKind::Closure | DefKind::AssocFn | DefKind::Fn => {
-            let ty_sig = match kind {
-                DefKind::Closure => match tcx.type_of(item).instantiate_identity().kind() {
-                    ty::Closure(_, args) => args.as_closure().sig(),
-                    _ => bug!(),
-                },
-                _ => tcx.fn_sig(item).instantiate_identity(),
-            };
             let hir_sig = tcx.hir().get_by_def_id(item).fn_decl().unwrap();
             // Walk over the inputs and outputs manually in order to get good spans for them.
             visitor.visit(hir_sig.output.span(), ty_sig.output());
@@ -61,7 +46,7 @@ pub fn walk_types<'tcx, V: SpannedTypeVisitor<'tcx>>(
                 Some(ty) => ty.span,
                 _ => tcx.def_span(item),
             };
-            visitor.visit(span,  tcx.type_of(item).instantiate_identity());
+            visitor.visit(span, tcx.type_of(item).instantiate_identity());
             for (pred, span) in tcx.predicates_of(item).instantiate_identity(tcx) {
                 visitor.visit(span, pred)?;
             }
@@ -74,13 +59,15 @@ pub fn walk_types<'tcx, V: SpannedTypeVisitor<'tcx>>(
         // Look at field types
         DefKind::Struct | DefKind::Union | DefKind::Enum => {
             let span = tcx.def_ident_span(item).unwrap();
-            visitor.visit(span,  tcx.type_of(item).instantiate_identity());
+            visitor.visit(span, tcx.type_of(item).instantiate_identity());
             for (pred, span) in tcx.predicates_of(item).instantiate_identity(tcx) {
                 visitor.visit(span, pred)?;
             }
         }
-        // Does not have a syntactical signature
+        // These are not part of a public API, they can only appear as hidden types, and there
-        DefKind::InlineConst => {}
+        // the interesting parts are solely in the signature of the containing item's opaque type
+        // or dyn type.
+        DefKind::InlineConst | DefKind::Closure | DefKind::Coroutine => {}
         DefKind::Impl { of_trait } => {
             if of_trait {
                 let span = tcx.hir().get_by_def_id(item).expect_item().expect_impl().of_trait.unwrap().path.span;
@@ -92,15 +79,11 @@ pub fn walk_types<'tcx, V: SpannedTypeVisitor<'tcx>>(
                 _ => tcx.def_span(item),
             };
             visitor.visit(span, tcx.type_of(item).instantiate_identity());
-            for (pred, span) in tcx.predicates_of(item).instantiate_identity(tcx) {
-                visitor.visit(span, pred)?;
-            }}
-        DefKind::Trait => {
             for (pred, span) in tcx.predicates_of(item).instantiate_identity(tcx) {
                 visitor.visit(span, pred)?;
             }
         }
-        DefKind::TraitAlias => {
+        DefKind::TraitAlias | DefKind::Trait => {
             for (pred, span) in tcx.predicates_of(item).instantiate_identity(tcx) {
                 visitor.visit(span, pred)?;
             }

tests/ui/coroutine/gen_block_panic.rs

@@ -0,0 +1,26 @@
+//compile-flags: --edition 2024 -Zunstable-options
+// run-pass
+// needs-unwind
+#![feature(gen_blocks)]
+
+fn main() {
+    let mut iter = gen {
+        yield 42;
+        panic!("foo");
+        yield 69; //~ WARN: unreachable statement
+    };
+    assert_eq!(iter.next(), Some(42));
+    let mut tmp = std::panic::AssertUnwindSafe(&mut iter);
+    match std::panic::catch_unwind(move || tmp.next()) {
+        Ok(_) => unreachable!(),
+        Err(err) => assert_eq!(*err.downcast::<&'static str>().unwrap(), "foo"),
+    }
+
+    match std::panic::catch_unwind(move || iter.next()) {
+        Ok(_) => unreachable!(),
+        Err(err) => assert_eq!(
+            *err.downcast::<&'static str>().unwrap(),
+            "`gen fn` should just keep returning `None` after panicking",
+        ),
+    }
+}

tests/ui/coroutine/gen_block_panic.stderr

@@ -0,0 +1,12 @@
+warning: unreachable statement
+  --> $DIR/gen_block_panic.rs:10:9
+   |
+LL |         panic!("foo");
+   |         ------------- any code following this expression is unreachable
+LL |         yield 69;
+   |         ^^^^^^^^^ unreachable statement
+   |
+   = note: `#[warn(unreachable_code)]` on by default
+
+warning: 1 warning emitted
+

tests/ui/coroutine/gen_fn.e2024.stderr

@@ -1,10 +1,10 @@
-error: `gen` blocks are not yet implemented
+error: `gen` functions are not yet implemented
   --> $DIR/gen_fn.rs:4:1
    |
 LL | gen fn foo() {}
    | ^^^
    |
-   = help: only the keyword is reserved for now
+   = help: for now you can use `gen {}` blocks and return `impl Iterator` instead
 
 error: aborting due to previous error
 

tests/ui/coroutine/gen_fn.rs

@@ -3,6 +3,6 @@
 
 gen fn foo() {}
 //[none]~^ ERROR: expected one of `#`, `async`, `const`, `default`, `extern`, `fn`, `pub`, `unsafe`, or `use`, found `gen`
-//[e2024]~^^ ERROR: `gen` blocks are not yet implemented
+//[e2024]~^^ ERROR: `gen` functions are not yet implemented
 
 fn main() {}

tests/ui/issues/issue-37534.rs

@@ -1,6 +1,6 @@
-struct Foo<T: ?Hash> { }
+struct Foo<T: ?Hash> {}
 //~^ ERROR expected trait, found derive macro `Hash`
 //~^^ ERROR parameter `T` is never used
-//~^^^ WARN default bound relaxed for a type parameter, but this does nothing
+//~^^^ WARN relaxing a default bound only does something for `?Sized`
 
-fn main() { }
+fn main() {}

tests/ui/issues/issue-37534.stderr

@@ -1,7 +1,7 @@
 error[E0404]: expected trait, found derive macro `Hash`
   --> $DIR/issue-37534.rs:1:16
    |
-LL | struct Foo<T: ?Hash> { }
+LL | struct Foo<T: ?Hash> {}
    |                ^^^^ not a trait
    |
 help: consider importing this trait instead
@@ -9,16 +9,16 @@ help: consider importing this trait instead
 LL + use std::hash::Hash;
    |
 
-warning: default bound relaxed for a type parameter, but this does nothing because the given bound is not a default; only `?Sized` is supported
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
-  --> $DIR/issue-37534.rs:1:12
+  --> $DIR/issue-37534.rs:1:15
    |
-LL | struct Foo<T: ?Hash> { }
+LL | struct Foo<T: ?Hash> {}
-   |            ^
+   |               ^^^^^
 
 error[E0392]: parameter `T` is never used
   --> $DIR/issue-37534.rs:1:12
    |
-LL | struct Foo<T: ?Hash> { }
+LL | struct Foo<T: ?Hash> {}
    |            ^ unused parameter
    |
    = help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`

tests/ui/issues/issue-87199.rs

@@ -6,11 +6,11 @@
 
 // Check that these function definitions only emit warnings, not errors
 fn arg<T: ?Send>(_: T) {}
-//~^ warning: default bound relaxed for a type parameter, but this does nothing
+//~^ warning: relaxing a default bound only does something for `?Sized`
 fn ref_arg<T: ?Send>(_: &T) {}
-//~^ warning: default bound relaxed for a type parameter, but this does nothing
+//~^ warning: relaxing a default bound only does something for `?Sized`
 fn ret() -> impl Iterator<Item = ()> + ?Send { std::iter::empty() }
-//~^ warning: default bound relaxed for a type parameter, but this does nothing
+//~^ warning: relaxing a default bound only does something for `?Sized`
 
 // Check that there's no `?Sized` relaxation!
 fn main() {

tests/ui/issues/issue-87199.stderr

@@ -1,20 +1,20 @@
-warning: default bound relaxed for a type parameter, but this does nothing because the given bound is not a default; only `?Sized` is supported
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
-  --> $DIR/issue-87199.rs:8:8
+  --> $DIR/issue-87199.rs:8:11
    |
 LL | fn arg<T: ?Send>(_: T) {}
-   |        ^
+   |           ^^^^^
 
-warning: default bound relaxed for a type parameter, but this does nothing because the given bound is not a default; only `?Sized` is supported
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
-  --> $DIR/issue-87199.rs:10:12
+  --> $DIR/issue-87199.rs:10:15
    |
 LL | fn ref_arg<T: ?Send>(_: &T) {}
-   |            ^
+   |               ^^^^^
 
-warning: default bound relaxed for a type parameter, but this does nothing because the given bound is not a default; only `?Sized` is supported
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
-  --> $DIR/issue-87199.rs:12:13
+  --> $DIR/issue-87199.rs:12:40
    |
 LL | fn ret() -> impl Iterator<Item = ()> + ?Send { std::iter::empty() }
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |                                        ^^^^^
 
 error[E0277]: the size for values of type `[i32]` cannot be known at compilation time
   --> $DIR/issue-87199.rs:18:15

tests/ui/or-patterns/exhaustiveness-pass.rs

@@ -35,4 +35,10 @@ fn main() {
         ((0, 0) | (1, 0),) => {}
         _ => {}
     }
+
+    // This one caused ICE https://github.com/rust-lang/rust/issues/117378
+    match (0u8, 0) {
+        (x @ 0 | x @ (1 | 2), _) => {}
+        (3.., _) => {}
+    }
 }

tests/ui/self/arbitrary-self-from-method-substs.default.stderr

@@ -0,0 +1,13 @@
+error[E0658]: `R` cannot be used as the type of `self` without the `arbitrary_self_types` feature
+  --> $DIR/arbitrary-self-from-method-substs.rs:8:43
+   |
+LL |     fn get<R: Deref<Target = Self>>(self: R) -> u32 {
+   |                                           ^
+   |
+   = note: see issue #44874 <https://github.com/rust-lang/rust/issues/44874> for more information
+   = help: add `#![feature(arbitrary_self_types)]` to the crate attributes to enable
+   = help: consider changing to `self`, `&self`, `&mut self`, `self: Box<Self>`, `self: Rc<Self>`, `self: Arc<Self>`, or `self: Pin<P>` (where P is one of the previous types except `Self`)
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0658`.

tests/ui/self/arbitrary-self-from-method-substs.feature.stderr

@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/arbitrary-self-from-method-substs.rs:14:5
+  --> $DIR/arbitrary-self-from-method-substs.rs:16:5
    |
 LL |     foo.get::<&Foo>();
    |     ^^^ expected `&Foo`, found `Foo`

tests/ui/self/arbitrary-self-from-method-substs.rs

@@ -1,10 +1,12 @@
-#![feature(arbitrary_self_types)]
+// revisions: default feature
+#![cfg_attr(feature, feature(arbitrary_self_types))]
 
 use std::ops::Deref;
 
 struct Foo(u32);
 impl Foo {
-    fn get<R: Deref<Target=Self>>(self: R) -> u32 {
+    fn get<R: Deref<Target = Self>>(self: R) -> u32 {
+        //[default]~^ ERROR: `R` cannot be used as the type of `self`
         self.0
     }
 }
@@ -12,5 +14,5 @@ impl Foo {
 fn main() {
     let mut foo = Foo(1);
     foo.get::<&Foo>();
-    //~^ ERROR mismatched types
+    //[feature]~^ ERROR mismatched types
 }

tests/ui/traits/item-privacy.stderr

@@ -8,11 +8,10 @@ LL |     S.a();
    |       ^ method not found in `S`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
-note: `method::A` defines an item `a`, perhaps you need to implement it
+help: the following trait is implemented but not in scope; perhaps add a `use` for it:
-  --> $DIR/item-privacy.rs:6:5
+   |
+LL + use method::A;
    |
-LL |     trait A {
-   |     ^^^^^^^
 
 error[E0599]: no method named `b` found for struct `S` in the current scope
   --> $DIR/item-privacy.rs:68:7
@@ -51,11 +50,10 @@ LL |     S::a(&S);
    |        ^ function or associated item not found in `S`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
-note: `method::A` defines an item `a`, perhaps you need to implement it
+help: the following trait is implemented but not in scope; perhaps add a `use` for it:
-  --> $DIR/item-privacy.rs:6:5
+   |
+LL + use method::A;
    |
-LL |     trait A {
-   |     ^^^^^^^
 
 error[E0599]: no function or associated item named `b` found for struct `S` in the current scope
   --> $DIR/item-privacy.rs:80:8
@@ -91,11 +89,10 @@ LL |     S::A;
    |        ^ associated item not found in `S`
    |
    = help: items from traits can only be used if the trait is implemented and in scope
-note: `assoc_const::A` defines an item `A`, perhaps you need to implement it
+help: the following trait is implemented but not in scope; perhaps add a `use` for it:
-  --> $DIR/item-privacy.rs:24:5
+   |
+LL + use assoc_const::A;
    |
-LL |     trait A {
-   |     ^^^^^^^
 
 error[E0599]: no associated item named `B` found for struct `S` in the current scope
   --> $DIR/item-privacy.rs:98:8

tests/ui/type-alias-impl-trait/infinite-cycle-involving-weak.rs

@@ -0,0 +1,8 @@
+#![feature(type_alias_impl_trait)]
+
+type T = impl Copy;
+//~^ ERROR cannot resolve opaque type
+
+static STATIC: T = None::<&'static T>;
+
+fn main() {}

tests/ui/type-alias-impl-trait/infinite-cycle-involving-weak.stderr

@@ -0,0 +1,9 @@
+error[E0720]: cannot resolve opaque type
+  --> $DIR/infinite-cycle-involving-weak.rs:3:10
+   |
+LL | type T = impl Copy;
+   |          ^^^^^^^^^ cannot resolve opaque type
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0720`.

tests/ui/type-alias-impl-trait/nested_impl_trait_in_assoc_ty.rs

@@ -0,0 +1,44 @@
+//! This test checks that we do not walk types in async blocks for
+//! determining the opaque types that appear in a signature. async blocks,
+//! all other coroutines and closures are always private and not part of
+//! a signature. They become part of a signature via `dyn Trait` or `impl Trait`,
+//! which is something that we process abstractly without looking at its hidden
+//! types.
+// edition: 2021
+// check-pass
+
+#![feature(impl_trait_in_assoc_type)]
+
+use std::future::Future;
+
+pub struct MemtableLocalStateStore {
+    mem_table: MemTable,
+}
+
+impl LocalStateStore for MemtableLocalStateStore {
+    type IterStream<'a> = impl Sized + 'a where Self: 'a;
+
+    fn iter(&self) -> impl Future<Output = Self::IterStream<'_>> + '_ {
+        async move { merge_stream(self.mem_table.iter()) }
+    }
+}
+
+trait LocalStateStore {
+    type IterStream<'a>
+    where
+        Self: 'a;
+
+    fn iter(&self) -> impl Future<Output = Self::IterStream<'_>> + '_;
+}
+
+struct MemTable;
+
+impl MemTable {
+    fn iter<'a>(&'a self) -> impl Iterator<Item = &'a ()> {
+        std::iter::empty()
+    }
+}
+
+pub(crate) async fn merge_stream<'a>(mem_table_iter: impl Iterator<Item = &'a ()>) {}
+
+fn main() {}

tests/ui/unsized/maybe-bounds-where.rs

@@ -11,11 +11,11 @@ trait Trait<'a> {}
 
 struct S4<T>(T) where for<'a> T: ?Trait<'a>;
 //~^ ERROR `?Trait` bounds are only permitted at the point where a type parameter is declared
-//~| WARN default bound relaxed for a type parameter
+//~| WARN relaxing a default bound only does something for `?Sized`
 
 struct S5<T>(*const T) where T: ?Trait<'static> + ?Sized;
 //~^ ERROR type parameter has more than one relaxed default bound
-//~| WARN default bound relaxed for a type parameter
+//~| WARN relaxing a default bound only does something for `?Sized`
 
 impl<T> S1<T> {
     fn f() where T: ?Sized {}

tests/ui/unsized/maybe-bounds-where.stderr

@@ -28,23 +28,23 @@ error: `?Trait` bounds are only permitted at the point where a type parameter is
 LL |     fn f() where T: ?Sized {}
    |                     ^^^^^^
 
-warning: default bound relaxed for a type parameter, but this does nothing because the given bound is not a default; only `?Sized` is supported
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
-  --> $DIR/maybe-bounds-where.rs:12:11
+  --> $DIR/maybe-bounds-where.rs:12:34
    |
 LL | struct S4<T>(T) where for<'a> T: ?Trait<'a>;
-   |           ^
+   |                                  ^^^^^^^^^^
 
 error[E0203]: type parameter has more than one relaxed default bound, only one is supported
-  --> $DIR/maybe-bounds-where.rs:16:11
+  --> $DIR/maybe-bounds-where.rs:16:33
    |
 LL | struct S5<T>(*const T) where T: ?Trait<'static> + ?Sized;
-   |           ^
+   |                                 ^^^^^^^^^^^^^^^   ^^^^^^
 
-warning: default bound relaxed for a type parameter, but this does nothing because the given bound is not a default; only `?Sized` is supported
+warning: relaxing a default bound only does something for `?Sized`; all other traits are not bound by default
-  --> $DIR/maybe-bounds-where.rs:16:11
+  --> $DIR/maybe-bounds-where.rs:16:33
    |
 LL | struct S5<T>(*const T) where T: ?Trait<'static> + ?Sized;
-   |           ^
+   |                                 ^^^^^^^^^^^^^^^
 
 error: aborting due to 6 previous errors; 2 warnings emitted